Under the framework of joint information embedding and lossy compression, an algorithm based on secret sharing and unequal protection is proposed. Comparing with arithmetic coding which compressed watermark length, our algorithm can dramatically reduce the amount of information bits embedded into video cover while guaranteeing watermarking authentication. Our algorithm not only improves compression efficiency but also adopts unequal protection strategy, thus improving watermark's robustness considerably. Furthermore, by making full use of dependency among neighbouring macroblocks, an adaptive watermarking algorithm based on motion vectors is proposed to effectively control motion vector's modification and guarantee video quality after watermarking. Experiments demonstrate that this algorithm not only keeps a small PSNR loss and satisfactory visual quality, but also shows resistance against frame-deletion attack.

The ideas and method about the realization of a scene simulation platform using Visual C++ and Direct SDK were introduced. The platform adopted the overall structure of "twin platform based on the shared core", and reusable framework and mechanism for the further development were founded. Three-tier design pattern of "function entity, collection management and user interface" improved code reusing. So the complexity of the problem was reduced, and the software development efficiency was improved. In this scene simulation platform, the management mechanism of extensible visual object was established, the display optimization of medium or small scene and rapid terrain-matching were realized, the functions of particle system-based special effects about rain, snow, smog and blast, etc, and creating, editing, playing and saving key frame animation were achieved. Finally, the applied example was researched.

The Authorization Management in Grid Systems has various structures. This paper proposes an identity-based authorization mechanism using IBE algorithm. Our scheme could satisfy the demands of the process from access requests committed by users to the authorized access control. The security level of the scheme is lower than the systems based-certificates. Because of its convenient, it is useful in light-weight grid systems.